1. Field of the Invention
The present invention relates to a semiconductor laser device having a lead frame on which a semiconductor laser chip is mounted and achieving superior mass production.
2. Description of the Background Art
A semiconductor laser device having a lead frame on which a semiconductor laser chip is mounted is called a frame laser. FIGS. 2 to 4A, 4B show examples of conventional frame lasers.
FIG. 2 shows a frame laser disclosed in Japanese Patent Laying-Open No. 2-266584, in which a first lead portion 20 on which a laser chip 24 is mounted extends approximately straight, and second lead portions 21, 22, which are to be electrodes, are bent within mold resin 23.
FIG. 3 shows a frame laser disclosed in Japanese Patent Laying-Open No. 6-45691, in which a tip end of a first lead portion 30 on which a laser element 34 is mounted is widened in the widthwise direction. This allows heat radiation to be superior to that of the example shown in FIG. 2. Second lead portions 31, 32, which are to be electrodes, extend straight within an insulation frame 33.
FIGS. 4A and 4B show a frame laser disclosed in Japanese Patent Laying-Open No. 10-209551, in which a first lead portion 40 on which a laser chip 44 is mounted extends approximately straight. This inhibits efficient release of the heat generated in the semiconductor laser, so that a heat radiating plate 45 is provided on the back side of first lead portion 40.
Moreover, the outer shape of mold resin 43 for fixing the leads is formed to have a partially-cut circular shape, to facilitate adjustment and to prevent the mold resin from rotating after adjustment. Second lead portions 41 and 42, which are to be electrodes, extend straight within mold resin 43.
In the example shown in FIG. 2, first lead portion 20 extends straight, so that heat generated in the semiconductor laser cannot efficiently be released, degrading reliability. In addition, the tip ends of second lead portions 21, 22 are bent, thereby increasing the size of the frame laser in the direction of a width W.
In the example shown in FIG. 3, heat radiation can be improved compared to the example shown in FIG. 2, as described above. However, second lead portions 31, 32 extend straight within insulation frame 33, resulting that second lead portions 31, 32 may come off because of softened insulation frame 33 when second lead portions 31, 32 are soldered to an external circuit. Moreover, second lead portions 31, 32 easily move and hence they may easily change their orientation.
In the example shown in FIGS. 4A and 4B, though a similar problem may occur such as coming off of second lead portions 41, 42, as in the case with the example shown in FIG. 3, a portion of mold resin 43 covering second lead portions 41, 42 is made thicker and a convex portion 46 is provided, so that the problem such as coming off of second lead portions 41, 42 may be prevented to some degree.
However, provision of convex portion 46 alone cannot sufficiently prevent coming-off or the like of second lead portions 41, 42. Moreover, in the example shown in FIGS. 4A and 4B, the use of a heat radiating member such as a copper block is required, which lowers productivity and increases cost.